Hot-blast stove



. 3 Sheets-Sheet .1] J. F. BENNETT.

HOT BLAST, STOVE (N0 Modal.)

Patented .Aug 5,1884.

(N0 Model.)

I a Sheets-Sheet 2. J. F. BENNETT.

HOT BLAST STOVE;

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3 Sheets-Sheet 3.

(No Model.)

' J. P. BENNETT.

HOT BLAST STOVE.

Patented Aug. 5, 1884.

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UNITED STATES JOHN F. BENNETT, on rrrrsnune, PENNSYLVANIA.

HOT-BLAST STOVE.

SPECIFICATION forming part of Letters Patent No. 303,203, dated August5, 1884.

Application filed September 24, 1883. (No modcLl To (1,15 whom it mayconcern.-

Be it known that I, J OHN Fnirncrs BENNETT, of Pittsburg, in the countyof Allegheny and State of Pennsylvania, have invented certain new anduseful Improvements in I-Iot-Blast Stoves; and I do hereby declare thatthe following is a full, clear, and exact description thereof, referencebeing had to the accompa nying drawings, and to the letters of referencemarked thereon, which-form part of this specification.

My invention relates to improvements in stoves for heating air-blastsfor blast-furnaces, in which atmospheric air, on its passage through thestove, takes up the heat previously deposited by the hot waste gasesfrom the blast furnace; and the obj ects of my improvements are, first,to facilitate the passage of the cold air through the stove; second, topresent a large heated surface to the air forced through; and,third, toattain these ends with simplicity of construct-ion. I attain theseobjects by the means illustrated in the accompanying drawings, inwhich-- Figure 1 represents an elevation ofmy stove, showing therelative location of the parts. Fig. 2 is a plan view of the same. Fig.3 is a sectional elevation, and Fig. 4; a horizontal section, thereof.

Similar letters refer to corresponding parts throughout the views.

A represents the tubes which form the flues a c a, by which the hot airis conducted from the blast-furnace flue e to the chimney-flue O, andthe cold air from the cold-air inlet M to the heated-air main F, whichleads to the furnace. The tubes are so shaped that the crosssection ofthe fines forms a hexagon, whereby a large surface for the storage ofheat is pre sented to the waste gases and a greater increment oitemperature imparted to the atmospheric air than heretofore possible.The ends of each tube are rounded or tapered to avoid frictionalresistance to the passage of the air or gas.

B is the valve-casing, in which a valve similar to G moves. Thevalve-stem on has a weighted lever, m, attached thereto, so that thehot. gases can only enter the stove when their pressure exceeds that ofthe weighted lever, the weight being horizontally adjustable to obtaindiilerent degrees of pressure. The

hot gases are admitted to the casing B from the blast-furnace by themain underground flue c and pipes (E D, and thence conducted to thestove by pipe A flanged cover, 7t, capable of vertical movement on theboX,-affords access to its interior for cleaning or inspection.

G is the main underground flue conducting the waste gases, after havingtraversed the stove and been largely, if not entirely, relieved of heatby contact with the tubes and the walls of the stove and pipes, eitherto the shaft or to a point of further utilization.

O is a valve regulating access of the waste gases to the flue 0. Itsvertical position dc termines the velocity of the hot gases and theamount of heat abstracted. To a handle, it, affixed to the valve-stem K,is attached a chai 11,. i, passing over the wheel f, supported by asuitable standard, G, on the valve-casing O. Weights l? P are attachedto the other end of the chain 1', to counterbalance the tendency of thevalve to approach its sea-t, caused by gravity and thcsuct-ion of th echimney. As the weights approach each other the strain on O isincreased.

U U are pipes connecting the valve-box O with the chimney-flue C. Aneye-piece, g, affords means for observing theinterior of the valve-box,and a man-hole, Q, ai'iords access thereto.

D is a pipe connecting the valve-box B with the pipe cl.

E is a duct having a valve, Z1, therein, by which the cold air requisiteto secure perfect combustion of the hot gases is admitted to the stove.v

F is the-pipe leading the heated atmospheric air from the stove to thefurnace. A valve, H, regulates the amount fed. A joint, Z, is providedto allow of ready access to the pipe.

G is a standard supporting the Wheel f.

IJ J J represent the four chambers through which the hot gas or heatedair is conducted, either to the chimney-flue C or to the heated air mainF, according as the respective source is the underground iluc e or thecold air pipe M.

K is the stem of the valve 0.

L L L L are a series of doors at the top of the stove, permitting accessto its interior for cleaningor inspection purposes.

M is a cold-air pipe having a valve, M.

N N N N are doors at the bottom of the furnace for cleaning orobservation.

0 is a passage, formed by arching the partition Z over the pier Z, bywhich the gases can go from the chamber J to J, and the heated air fromJ to J, the gases and air pursuing opposing directions.

P an d I are counterweights for the valve 0.

Q is a man-hole to admit access for cleaning the valve 0, valve-box O,and pipes R and U.

R is a pipe connecting the chamber J with the valvc box G.

S represents the iron casing of the stove. The stove is preferably madeof an altitude of seventy feet and a diameter of twenty-one feet.

T represents a nut affording a bearing for the valve-stem K and guidingits vertical reciprocation.

U U are pipes connecting the valve-box O with the underground flue O.

V is the air-space between the casing S and the briclcwork W, to obviateconduction.

W" W WV WV are large stones, which can be removed to afford access,respectively, to the chambers I J J J by first opening the series ofdoors L L L L and removing the stones L L L L. Y

X X X are cross-walls sustaining the wall Z in position.

Y.Y Y Y Y Y are large stones supporting the tubes A A A in position. Thestones are so cut as to form a quadrant in one corner, thereby formingan arch when two stones, counterpart each of the other, are placed inthe position illustrated on the drawings, whereby maximum strength issecured.

Z Z Z Z are the brick partitions forming the chambers I J J J.

Z is a pier, upon which the arched stones forming the passage 0 rest.

The operation is as follows: The valve, whose stem is indicated by m, isopened, allowing the access to the stove of the blast-furnace, hot gasescoming through the flue e and pipes d D into the valve box B, and thenceinto the stove by pipe 0. Simultaneously the cold-air valve 1) is openedin the pipe E to secure perfect combustion of these gases in the stove..

The valves H and M being closed at this time, the hot gases will govertically through chan1- her I, be deflected by the arch into the fluesa a a, composing chamber J, thence through arched passage 0 into thebottom of the chamber J, through fl'ues a a a of that chamber, againdeflected by a similar arch, and thence out through flues a a a ofchamber J into pipe It, valve-box G, pipes U U, flue G, and thence tothe chimney with or without intermediate utilization. The gasestraversing the walls and fines at a temperature approximately 2,500Fahrenheit, and a velocity regulated by the position in avertical planeof the valve G, de posit their heat, to a greater or less amount,according to the velocity, in the walls IV Z Z Z Z and the tubes A A Ain the chambers J J J, which serve as storage-reservoirs for this heat.\Vhen the stove has been raised to the desired temperature, thevalves 1) O and that in the box B are closed, and the valves M and H inthe pipes F M opened, which lead,

respectively, to the blast-furnace and the blow-- er. The cold air thentraverses the stove in an opposing direction to that pursued by the hotgases, and takes up the heat previously deposited there by the gases.

As the fiues are hexagonal in their crossseetion, instead of round,square, or parallelogranimatic, as fheretofore, more heat is abstractedfrom the gases than possible with the round flue, first, because of adecrease in velocity, owing to the shape of the path; and, second, onaccount of an increase in the convex surface which takes up the heat,because the convex surface of a prism is measured by the product of theperimeter by the altitude,

while that of the cylinder is measured by the product of thecircumference by the altitude,

the altitude and diameter being taken, respect-.

ively, the same; but the area of the polygon circumscribed about acircle is greater than that of the circle; hence the area of the prismhaving the same diameter and altitude as the inscribed cylinder isgreater than that of the latter.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent of the United States, is-

1. In apparatus for feeding heated air to blasti'urnaces, a stove havingits walls and tubes shaped hexagonally in their cross-section, for thepurpose specified.

2. In apparatus for feeding heated air to blast-furnaces, a stove, S,having hexagonallyshaped partition-walls Z Z Z Z, and hexagonal tubes A,the walls forming chambers I J J J, substantially as described.

3. In apparatus for feeding heated air to blast-furnaces, a stove, S,having flue e, pipes 01 D, box B, containing a valve, pipe 0, pipe E,containing valve 1), hexagonal tubes A, partitions Z Z Z, formingchambers I J J J, passage 0, pipe It, valve-box C, containing valve 0,pipes U U, and flue O, for the purposeherein fully set forth.

4. In apparatus for feeding heated air to blast-furnaces, a stove, S,pipe M, provided with a valve, hexagonal tubes A, partitions Z Z r Z,forming chambers I J J J, passage 0, and pipe F, containing valve H, forthe purpose described.

5. In apparatus for feeding heated air to blast-furnaces, astove, S,havingaflue, c, pipes cl D, box B, containing a valve regulated by aWeighted lever, m, attached to stem m,'pipe a, pipe E, containing valveb, hexagonal tubes A, partition-walls Z Z Z Z, forming chambers I J J J,passage 0, pipe R, valve-box 0, containing valve 0, whose verticalreciprocation is regulated by counter-weights P P, attached to one endof a cord or chain, i,whose other end is affixed to the handle is of thevalve-stem K, the cord 6 passing over pulleywheel f, suitably supportedon or over the valve-box by a standard, G, pipes U U, and flue C, forthe purpose herein fully specified.

6. In apparatus for feeding heated air to blast-furnaces, a stove, S,having a flue, e,

pipes (l D, box B, containing a valve regulated by a weighted lever, m,attached to stem m, pipe a, pipe E, inolosing valve 6, hexagonal tubesA, partition-walls Z Z Z 75', forming chambers I J J J, passage 0, pipeR, valve-box G", containing valve 0, whose vertical reciprocation iscontrolled by counter-weights P P, attached to one end of a cord orchain, 2, whose other end is efiixed to the handle 70 of the valve-steinK, the cord z'pass- I 5 ing over apulley-wheel, f, suitably supported onthe valve-box by a standard, G, pipes U U, flue O, pipes M F, and theirinelosed valves M H, for the purpose herein described.

In testimony that I claim the foregoing as 20 my own I affix mysignature in presence of,

two witnesses.

JOHN F. BENNETT. \Vitnesses:

M. E. Hnumsorr, ALEX. RANDOL.

